Nonfoaming oil composition containing polymeric silicone



Patented Mar. 18, 1952 UNITED STATES PATENT OFFICE NONFOAMING OIL COMPOSITION CONTAIN- INGI POLYMERIC SILICONE David V Young, Roselle, and Salvatore George Gallo, Elizabeth, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application January 10, 1945, Serial No. 572,258

hydrogen in a structure corresponding to some extent to those of aliphatic carbon type compounds by the proceduresgiven in U. S. Patents Nos. 2,258,218 to 2,258,222 inclusive as well as U. S. Patent No. 2,352,974. 'The structural formulae postulated for this class of compounds are, as well as can be judged:

The exact nature of the terminal portions of the molecule is not as yet definitely known. However, the resulting silicon chain compounds are found to have from about 6 to about 18 silicon atoms in the chain, with a corresponding number of interposed oxygen atoms, and a double number of methyl substituents.

Thismaterial may be identified chemically as hydrocarbon substituted silicon others or silicones. It is now sold as Dow-Corning Fluid 200 under several viscosity ranges. The material is available commercially under several difierent identification numbers such as Dow-Corning Fluid 1V5, or Dow-Corning Fluid 200, or Dow- Corning Fluid 1000, or the like. The physical properties of various grades of this material are shown inthefollowing Table 1:

The Dow-CorningFluldZOO is soluble in several solvents andcda'taon solubility tests will be found in Table 2:

TABLE 2 Solubility of Dow-Corning Fluid 200 or Sili- Completely Misclblc figiggi z i r r I i Benzene Dioxan i Xylene Butyl phthalote Chloroform Ethylene glycol Carbon tetrachloride Ethanol Tri chlor ethylene Methanol N-Butyl chloride Iso-propanol N-Arnyl alcohol Dichlordiethyl other Ethyl Acetate Nitrobenzene Carbitol acetate Lubricating Oll Partly soluble Soluble from 1% to 10% by weight in the Solvent) Butanol Acetone Acetic anhydride These silicones, particularly the lighter grades are of particular value in the heavy lubricating oils as a means for reducing the tendency towards foaming, as in aviation engine oils when the air pressure is greatly reduced. The solubility of these compounds, however, especially in the intermediate range of hydrocarbons such as the light lubricating oils, reduces their effectiveness as anti-foaming agents in the lighter petroleum lubricants.

The present invention is based upon the discovery that these silicon compounds, commonly known as silicones are susceptible to a polymerization by the use of halogens or metal halides especially bromine or metal bromides, with or without a subsequent treatment with water, particularly the Friedel-Crafts type of metal bromides.

These silicon compounds are available in a range of viscositles as above indicated. The lighter grade, containing approximately 6 silicon atoms per molecule, has a molecular weightoi approximately 3'74, whereas the heavier grade containing approximately 12 silicon atoms has a molecular weightof approximately 698.

By treatment according to the presentinvention, these silicon compounds can be polymerized vinto;polymers containing from to 125 or more silicon atoms. The upper limit is at the present time unknown but is believed to be well above 11,000, 2,000 or 3,000, depending upon the efficiency ,of the polymerization step. A polymercontaln- 'ing silicon atoms will have a molecular weight in the general neighborhood of 3,000. Since, however, the terminal groupings on the silicon chain are as yet unknown and the character of the polymerization is as yet unknown, the precise molecular weight cannot be stated for any given number of silicon atoms in the chain.

The resulting silicone polymer, having a much caoutchouc, or the lower temperature interpolymer of isobutylene with a polymer such as isoprene, as well as the other rubber-like substances including polychloroprene and the other analogous substances.

Thus, the invention polymerizes silicone substances into relatively high molecular weight polymers which are useful with various hydrocarbons; as anti-foaming agents for lubricating oils and softeners for rubber and as mold and stopcock lubricants. Other objects and details of the invention will be apparent from the following description:

The raw material for this invention is the sillcone substance which is prepared as shown in the above mentioned patents. This material is prepared by the Grignard reaction. That is, a silicon tetra halide such as silicon tetra chloride is mixed with an organic oxy halide which is preferably an alkyl oxy halide such as methyl oxy bromide, but may alternatively be any other type of organic compound containing both oxygen and halogen; with a metal such as magnesium which will remove the halogen simultaneously from both the silicon halide and the organic oxy halide; followed by hydration of the resulting alkyl or aryl silicon halide and subsequent dehydration of the organo hydroxy silane to form silico oxy chain structures containing hydrocarbon substituents of the type illustrated in the above presented structural formula.

The commercially avaliable silicon oils are produced by the general reaction above described with or without many minor variations;

. and our present invention utilizes these silicone oils prepared by the above-mentioned process steps in a polymerization reaction to form new products of higher molecular weight with -markedly altered and improved properties.

According to the reaction of the present invention these water-white silicon oils or compounds are treated with a bromine compound which may be either elemental bromine in solution in a suitable inert solvent such as carbon tetrachloride or the like, or may be a Friedel- Crafts type bromine compound such as an aluminum bromide or titanium oxy bromide or The polymerization reaction can be conducted over a considerable range of temperatures. Usually it is preferable to conduct it at room temperatures in the neighborhood of 18 to 20 C. Alternatively, temperatures down as low as 0 C. are suitable, and temperatures as high as 200 C. are similarly feasible. It may be noted that mere heating of the pure silicon oils by themselves to temperatures as high as C. .for as long as four weeks produces little or no change in their properties; whereas treatment of the same oils with a small quantity of a dilute solution of bromine in carbon tetra chloride for comparable time intervals, even at room temperature, results in a progressive increase in the viscosity of the oil until a rubbery, tacky gel is produced. The reaction yields the desired polymer which is found to be a rubbery gel which may vary from a completely opalescent to a water-white plastic mass exhibiting some resilience and tensile strength.

The resulting polymer may be separated from the bromine compounds in any convenient way and purified either by mechanical separation from residual solids or washing with water. If prepared with dilute bromine solution no further treatment is necessary unless it is desired to quench the reaction. When prepared without water treatment the resulting polymer exhibits a very high degree of permanent tack which imparts to it high film strength and, consequently, improved lubricating properties.

The resulting plastic polymers are found to have a much lower solubility in organic solvents as well as water, rendering them unusually suitable as stopcock lubricants and defoaming agents. Silicone oils modified in this way serve as superior defoaming aids or additives for mineral oils, mineral oils containing organic sulfonates, and especially those having a flash point below 425 F.

EXAMPLE 1 A mixture was prepared at room temperature or approximately 19 C., consisting of 10 parts by weight of Dow-Corning Fluid, viscosity grade identified as 200 with 25 parts by weight of liquid boron tribromide (BBI's). The reaction proceeded prompty and after about 30 seconds became noticeably warm. After about 5 minutes the temperature of the reaction mixture was found to be between 50 and 60 C. The warm mixture was then mixed with 500 parts by weight of cold water to remove the boron tribromide by hydrolysis. The silicone polymer product floated on the water in the form of a semi-solid to solid resin with'the boron and bromine remaining in the water. The solid-silicone polymer was removed from the top of the cold water and placed in a large flask nearly filled with cold water. The mixture was then brought up to the boiling point and the slightly colored silicone polymer was washed in the boiling water for approximately 1 hour. The solid polymer was then separated and the residual water was worked out from the rubbery solid gel by kneading. The solid gel was then allowed to dry at room temperature for two days. An analysis of the resulting material showed it to contain:

18.80% carbon 3.24 hydrogen 37.20% silicon 35.72 oxygen 5.10% boron :a'gsao am The resultingproduct was-then tested for-its anti foaming properties by the following procedure:

A solution wasprepared; consisting of 2.5 of the silicone-polymer inthe desired oil.- fi portion consisting of 200 grams: ofthesolutiorr-wasrthen placed in a malted milk mixer: cup and th'e height of the all solution inthe: cup was' measured. The solution was then. stirred inthe' mixer. cup for 3. minutes using the regulation stirrer speed of about 4,000 R. P.-

and". the; regulation: stain-en consisting at a: small" square metal member.- approximately: on" each; side and. A. thick; attached. to the lower end of; 21,1 diameter-steel rod"; The: height of. the: material. irrthe: beaker was: measured immediately afte ttermination of the. stirring. to'show thedncrease dueto; thepresence of foam. Another portion: of the. same oil,

without dissolved. silicone. polymer: therein, was.

then placed .in the. same 1.cup,.stirredifor. thdrsame length of. time-and the .foamheight measured; The diiference in".foamheightobtained with the solutiom compared to that. obtainedwiththes. oil alone,.,. is. a. measurement of. ther antiefoam'ing properties of. the silicone: polymer-.1 Applying this ,test. to. the: silicone: polymers, the following results: were" obtained? i Oil. ;Volume.' Increase Pt-r cent Aliglit'gasjoil 1 55 A light gas oil 0.001% Dow-CorningFluid No.200i. 75

A light gas 0il+ 0.001% Boron 'Bromide TreatedSiliaon 5 A Detergen ted. Oili-k 0.001% Boron Bromide 'l'reated.

SiliconePolymer"; 3 4

The results show that with a very=light oil; the silicones. as. suchincrease. rather thanredu'ce the foamingproperties. of. the. oil,., whereas the: polymers asaboveprepared, show. a. very greattantie foaming. power... They show also anequa'llyeffective anti-foamingpower with. the moderately heavy oils, althoug-h the increase i'n ant'il-foaming; power W-iththe heavyv oils. is not verygreat. EXAMPLE. 2:

Fifty parts'by weight of polysilicon'e. 1000 (Dow corning.;Flui'di 200;, Visc. 25 1000" c'stks) were mixed. intimately with about" 5' grams AICIk. and heatedin'an oven at11l0" C; overnight: The clear fluid was separated from residual";solids by means 'of a Buchner funneliand then stirred vigorously with one third" its volume' 'of" water.

A tacky; rubbery gel' was-formed. This gel was then-subjected to' high vacuumand except for appreciable frothi'ng during the': removal of entrapped water; theproduct. did not;janpear to change-in physical properties:

6 analyzed? and found i tohave': the following composition:

The-polymer was analyzed and foundto'have'tfie following composition:

It maybenoted.that-nobromine :or titaniunnawpears in either: of these; analyses althougha tests weremade. for both substances. Much of the bromine added ingthe catalyst was evolved as hydrogen bromide; during: the polymerizationre? actions The polymer was careiully'washed after the completion ofthe. polymerization reaction; and during this washing step, an. opalescence appeared both in .the'polymer. and in the wash water. This opales'cence appears to have been dueto the. presencejoftitanium compounds produced by'hydrolysisbfi the-titaniumoxy bromide; liberating; further. portions of. hydrogen. bromide andprecipitating.titaninmsaltswhicheventually become"- titanium dioxide. It. may vfurther be noted that. the polymer: does. not J wet titanium: dioxide; whereas. water does, and accordingly, the titanium compounds are entirely removed; .from thei polymer;

Thirty parts by weight of silicone 1000 were mixed thoroughly witli one or two parts 05% bromine in carbon tetrachloride. and placed iman oven. at 110 C. overnight It was then.permi-tted to stand at. room temperature. Atithenendot about: 3.- or 4- weeks-,it was: noted that; a: clear rubbery gel 3 had-formed.

EXAMPLE. 5

100. parts of mineral. oil hayingia. viscosity at 2110?" of 57 S. S. U i and a" viscosity index of '94 were. treated with three parts ofia detergent'compound; and. after a'iclea'r mixture was obtained at 150-190 0.15 parts of a. metal hydroxide were added; At this'spointi 0.0005 part of. the silicon polymer, as"? made in Example 2.1mm added; The mixture was then heated to 250 F1 for. one hour to. remove the water-formeddn" the reaction. 'm

The. gel type silicon polymer prevented the mixture. from froth'in in the, reactoras the water vapor was removed? heat.

The silicone polymer as made accordingitosEx'tample 2 was found to be very effective as a..softening; agent and. plasticizer. for? synthetiapolymerssu'ch: asisynthetie rubbers. The material. is:

' compatible:v with the- .b utadienemcrylonitrile co.-

polymer, Perbu'nan, to. the; extent; of. approxi-a mately' 15. parts of. the silicon. polymer per 100. parts: of; the butadienej acrylonitrile".polymer:

A. compound. was. prepared; consisting: oi;

Y Parts Perbunan Silicone" polymer '13 Zinc oxide 5c Stearic acid. "1

Sulfur 1.5 Channel black; -50? 'Altax benzo thiazyl disulfide) 1.

This material was prepared without serious difilculty although the disbursing of the silicon polymer into the Perbunan was attended with a minor difficulty as related to milling time. Portions of the resulting compound were cured in moulds at a temperature of 287 F. for 60 minutes and tested. The following test inspection results were obtained:

Tensile strength, 1750 lbs. per sq. inch Elongation, 335% Modulus at 300%, 1260 lbs. per sq. inch '1 A sample of the cured Perbunan was placed in a sample of gasoline having a high aromatic content and allowed to soak at room temperature for 7 days. The cured compound absorbed gasoline to yield a swell value of 78%. The swell sample was then dried in an air oven at a temperature of approximately 250 F. for -3 hours to remove the gasoline and it was then found to have a shrinkage of 0.3% over its original volume, showing that very little of the polysilicone plasticizer is extractable.

. a EXAMPLE f7 100 parts of Polybutene, 130,000 m. wt. Standinger were placed on a rubber mill and compounded for minutes at 175 F. with 3 parts of polysilicon gel plasticizer as made in Example '3. The Mooney viscosity of the mixture at 212 F. was 74; The same Polybutene, milled for 10 minutes on the same mill at 175 F. was found to have a Mooney viscosity at 212 F. of 68. The results showed that high In. wt. Polybutene could be plasticized with the cross linked gel type polysilicon.

.- EXAMPLE 8 100 parts of G-RS (butadiene-styrene copolymer) were placed on a rubber mill and compounded for 10 minutes at 220 F. with 4 parts of polysilicon gel plasticizer as made in Example 3. The Mooney viscosity of the mixture at 212 F. was 44. The same GRS (butadiene-styrene copolymer) milled for 10 minutes on the same mill at 220 F. was found to have a Mooney viscosity at 212 F. of 53. The results indicated thatthe copolymer was plasticized by the cross linked gel type high molecular weight polysilicon. The silicone polymer is equally effective for the plasticization of natural rubber or for theplastieization of natural rubber or for the plasticization of polychloroprene (sold on the marlgetas Duprene or neoprene); and equally. effective for the plasticization of the low temperature interpolymer of isobutylene with a polyolefin prepared as shown in U. S. Patents 2,356,127-8; and equally effective in the plasticization and treatment of the polymer resulting from the reaction between dichloro ethylene and sodium polysulflde.

- 1 Thus the process of. the invention polymerizes a silicone compound, consisting of a chain of alternate silicon and oxygen atoms, having methyl substituents attached to the silicon atoms, to yield a relatively high molecular weight polymer, with or without included bromine, and with or without additional amphoteric metals to yield semi-solid to solid silicone polymer which has very low solubility in lubricating oil; a much higher anti-foaming Power in lubricating oils generally, and is an effective softening and plasticizing agent in rubber substances generally.

3 :While there are above disclosed but a limited number of embodiments of the process and uses of the invention, it is possible to provide still other embodiments without departing from the inventive concept herein disclosed, and it is therefore desired that only such limitations be imposed upon the appended claims as are stated therein or required by the prior art.

The invention claimed is:

1. An improved oil composition comprising a major proportion of a hydrocarbon oil of the gas oil to lubricating oil viscosity range, having dissolved therein a foam-reducing amount of an oil-soluble solid gel repolymerization product of a liquid hydrocarbon-silicone polymer, said repolymerization product having been formed through the use of a bromine-containing catalyst at a temperature of about 0 to 200 C., said bromine-containing catalyst being selected from the group consisting of elemental bromine and Friedel-Crafts metal bromides.

2. An oil composition comprising a major proportion of a petroleum hydrocarbon oil of the gas oil to lubricating oil boiling range having dissolved therein a foam-reducing amount of about .0005% to 2.5% by weight of an oil-soluble solid gel repolymerization product of a liquid dimethyl silicone polymer having a molecular weight less than 1,000 and having about 6 to 18 silicon atoms per molecule, said repolymerizatlon product having a molecular weight of about 1,000 to 3,000 and having a molecular weight substantially above. 1,000, and said repolymerization product having been formed through the use of a bromine-containing catalyst at a temperature between about room temperature and 0., said bromine-containing catalyst being selected from the group consisting of elementalbromine and Friedel-Crafts metal bromides.

3. Composition according to claim 2 in which the repolymerization product has approximately the following chemical analysis:

Carbon 36.1

Hydrogen 7.41 Silicon 32.72

Oxygen 23.77

4. An oil composition comprising a major proportion of a hydrocarbon oil of the gas oil to lubricating oil viscosity range, having dissolved therein about .0005% to 2.5% of an oil-soluble solid gel repolymerization product of a liquid dimethyl silicone polymer having essentially the empirical formula [sl(CH3)2-O]n, where n is about 6 to 18, said repolymerization product having been made with a Friedel-Crafts metal bromide 'repolymerizing agent at a temperature of about 0? C. and 200 C.

5. Composition according to claim 4 in which the repolymerizing agent is boron bromide.

6. Composition according to claim 4 in which therepolymerizing agent is titanium bromide.

7. An oil composition comprising a major proportion of a petroleum hydrocarbon oil of the gas oil to light lubricating oil boiling range having a flash point below 425 F., having dissolved therein a foam-reducing amount of about .0005% to 2.5% by weight of an oil-solublesolid jgel repolymerization product of a liquid dimethyl silicone polymer having a molecular weight less than l,000 and having about 6 to 18 silicon atoms .bromide as catalyst at a temperature between about room temperature and 110 C., and said repolymerization product being composed of ,carbon, hydrogen, silicon, oxygen and boron.

8. Composition according to claim 7 containing gas oil as the base stock, and containing dissolved therein about 0.001% of a repolymerization product having approximately the following.

chemical analysis:

carbon hydrogen silicon oxygen boron formed through the use of an active halogencontaining catalyst selected from the group ofv the halogens bromine and chlorine and Friedel Crafts metal halides thereof, at a temperature of about to 200 C., and said repolymerization product having an average of about 75 to 125 silicon atoms per molecule but having a sub stantially lower proportion of an element selected from the group consisting of silicon and carbon than in the silicone polymer prior to repolymerization, as a result of a condensation polymerization.

10. Composition according to claim 9 in which the repolymerizing agent is elemental bromine.

11. Composition according to claim 9 in which the oil base stock is a gas oil.

12. An oil composition comprising a major proportion of a petroleum hydrocarbon oil of the gas oil to lubricating oil boiling range having dissolved therein a foam-reducing amount of about .0005% to 2.5% by weight of an oil-soluble solid gel repolymerization product of a liquid dimethyl silicone polymer having a molecular Weight less than 1,000 and having about 6 to 18 silicon atoms per molecule, and having substantially the following chemical analysis:

Carbon 32.46 Hydrogen 8.27

10 Silicon 36.56 Oxygen 22.71

said repolymerization product having a molecular weight of about 1,000 to 3,000 and having substantially the following chemical analysis:

Carbon 36.1 Hydrogen 7.41 Silicon 32.72 Oxygen 23.77

13. Composition according to claim 12, the repolymerization product having been formed through the use of titanium bromide at a temperature between room temperature and C., and said repolymerization product resulting from a silicon-removing condensation polymerization.

DAVID W. YOUNG. s. GEORGE GALLO.

REFERENCES CITED 3 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,016,027 Shinkle Oct. 1, 1935 2,080,363 Stocklin May 11, 1937 2,224,359 Rosenblum Dec. 10, 1940 2,371,068 Rocaon Mar. 6, 1945 2,375,007 Larsen et al. May 1, 1945 2,375,998 McGregor May 15, 1945 2,383,827 Sprung Aug. 28, 1945 2,389,477 Wright et al. Nov. 20, 1945 2,406,671 Diamond Aug. 27, 1946 2,407,037 Sowa Sept. 3, 1946 2,423,497 Harmon July 8, 1947 2,459,387 McGregor Jan. 18, 1949 2,464,231 Hersh Mar. 15, 1949 2,466,642 Larsen Apr. 5, 1949 2,467,976 Hyde Apr. 19, 1949 FOREIGN PATENTS Number Country Date Great Britain Jan. 1, 1947 

1. AN IMPROVED OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A HYDROCARBON OIL OF THE GAS OIL TO LUBRICATING OIL VISCOSITY RANGE, HAVING DISSOLVED THEREIN A FOAM-REDUCING AMOUNT OF AN OIL-SOLUBLE SOLID GEL REPOLYMERIZATION PRODUCT OF A LIQUID HYDROCARBON-SILICONE POLYMER, SAID REPOLYMERIZATION PRODUCT HAVING BEEN FORMED THROUGH THE USE OF A BROMINE-CONTAINING CATALYST AT A TEMPERATURE OF ABOUT 0 TO 200* C., SAID BROMINE-CONTAINING CATALYST BEING SELECTED FROM THE GROUP CONSISTING OF ELEMENTAL BROMINE AND FRIEDEL-CRAFTS METAL BROMIDES. 